Share Certificate
  
Credit unions are organized differently than banks. You might not be able to tell at first glance. Most of the functions are very similar. However, the underlying structure is quite different.
Some of the things that happen at the credit union have different names than similar functions at a bank. At a bank, you might buy a certificate of deposit, or CD. It's a short-term investment that pays more interest than the lousy rate you get in your savings account. At a credit union, this form of investment results in a share certificate.
It's the same basic outcome: you tie up your money for a set period of time. In exchange, you get a higher return than you would with a simple bank account.